It's been five years since the terrorist attack on the State Department annex in Benghazi, Libya, left four American servicemen dead. As Hillary Clinton begins her whirlwind book tour for “What Happened,” many Americans are still wondering what went wrong on that dark day in U.S. history.

Now, security personnel for a contracting firm that was hired to protect the diplomatic compound are coming forward with their claim that they were “silenced” about security lapses.

As Brad Owens and Jerry Torres told Tucker Carlson of Fox News in an interview, Torres Advanced Enterprise Solutions (TAES) was pressured to stay silent about the security problems that led to the deaths of the four Americans.

“A U.S. ambassador is dead and nobody is held accountable for it. And three guys … all died trying to defend him,” Torres, a Green Beret veteran and the firm's CEO, told Carlson.

Screenshot/Fox News

Former Army intelligence officer Brad Owens added, “Those who made the poor choices that actually, I would say, were more responsible for the Benghazi attacks than anyone else, they're still in the same positions, making security choices for our embassies overseas now.”

Fox News confirmed that the firm bid on the security contract for the Benghazi diplomatic annex, but it was ultimately awarded to The Blue Mountain Group.

Owens characterized The Blue Mountain Group's security resources.

“Blue Mountain U.K. is a teeny, tiny, little security company registered in Wales that had never had a diplomatic security contract, had never done any high threat contracts anywhere else in the world that we've been able to find, much less in high threat areas for the U.S. government. They had a few guys on the ground,” he said.

Among the issues for the security failure cited by Fox News's Catherine Herridge in her report were:

“The Blue Mountain Group hired guards through another company who were not armed.”

Owens said that it was well-known after fall of dictator Moammar Gaddafi the security situation was “deteriorating” and terror groups were flooding Libya.

Yet, the late Ambassador Christopher Stevens' requests for security enhancements went unheeded.

By Aug. 31, 2012, the State Dept. reportedly asked TAES to intervene. Owens says this is an “admission of the mistake of choosing the wrong company.”

Owens and Torres claim the State Department's contracting officer, Jan Visintainer, “absolutely” silenced their witness testimony about the security collapse.

"[Visintainer] said that I and people from Torres should not speak to the media, should not speak to any officials with respect to the Benghazi program,” Torres said.

The security contractors also gave their proscription for what might improve diplomatic security abroad.

Molly Riley-Pool/Getty Images

“In 1990, Congress passed a law that required contracts of this nature to go to the lowest bidder that's technically acceptable,” Owens said. “Now, what that has created is a race to the bottom, is what we call it. So basically, every company tries to cut every corner they can for these contracts.”

“Let's just say there's been a change at management at Department of State,” Owens also said. “I feel now that, given that the politics has been taken out of the Benghazi situation, now that there's no longer a candidate or anything related to it, a change of administrations, that actually, we have an opportunity here to fix the problems that made it happen.”